Important update regarding LTE modem updates
Due to the increasing number of reports from users that the Sequans modem and FiPy/GPy are becoming unresponsive if the firmware upgrade fails, I have been investigating this issue intensively during the last few days.
I have now discovered two issues that cause the modem to become "bricked".
We have now received two corrections from Sequans that allow us to update the boot loader of the modem to ensure that the modem will always remain in a recoverable state. While the initial tests looks promising, I require a few more days to make sure that the new scripts and updated files will no longer brick the modem. Due to this we have decided to take the current firmware files and updater scripts offline and we highly suggest you do not try to update your modem until we can deliver scripts to do so safely.
For those of you who have already bricked your modems, please let me apologise first of all that it took so long to discover the issue. We have updated more than a hundred modules ourselves without ever having any issues, so it took some serious effort to actually brick the modems in order to analyse and solve the issues.
We will keep updating you on this over the coming days. I understand and share your frustration in the matter but we're working as hard as possible to get these issues sorted.
Thanks a lot for your patience.
Kurt Renauer last edited by
@dan thanx a lot for feedback, can't wait to see band=8 and isattached=true !
We are working on the additional bands with Sequans. We will post an update when we have more information. Thanks for your patience
In regards to band 8, I was informed now that, while the hardware supports all bands (1,2,3,4,5,8,12,13,18,19,20,28), the Sequans firmware currently only supports a maximum of 6 bands so we chose the ones that gave us the best support at the time of launch. I have a call with Sequans later today to discuss this limitation and provide a firmware that can be used with band 8 as soon as possible. I hope to have an update on that within 24 hours.
The six bands that Pycom chose - i.e., the only ones currently supported by Sequans FW - are 3/4/12/13/20/28. We raised this issue about 8 months ago (https://forum.pycom.io/topic/2496/gpy-readiness/17), but still no progress.
@tuftec I've read them all, and the conclusion is not obvious. Therefore I ask, if you have another source.
It appears that the Sequans modem is not currently configured for band 8 support. A new firmware update is required.
@tuftec What is your source of the missing band 8 support? Doers it tell that the Sequans firmware, or the Pycom firmware, not passing the request to the Sequans firmware.
If I compare the behavior between band 20 and band 8, it looks pretty similar. All commands are accepted, and then the Sequans modem is reporting alternating CEREG 2 and CEREG 0 on its TX line, only the period is different. For band 20, the period is 45 seconds, for band 8 it is 225 seconds.
@robert-hh still wait on a response to band 8 support.
It appears that it is currently not supported.
This has put a halt to our developments at present.
robert-hh last edited by robert-hh
@xykon Today I got the information that T-Mobile Germany uses band 8 for NBIoT (900 MHz band). So it would be useful to know, if this band is supported by the Sequans firmware is the attach is requested by the command
Trying to do that did not succeed even after 2 hours waiting.
AT+CSQtells me, that a cell is seen and a good signal can be received. But I have to go through a hard reset to get that.
serafimsaudade last edited by serafimsaudade
I'm from Portugal, and I doing some testing the MEO NB network with 2 modems.
1 - Mangohred WP7702
2 - Pycom Gpy
I can connect with wp7702, and send data to our cloud server over UDP, MQTT. I also check the band use by the modem to connect, and is using the band 20.
With pycom, I try this code:
lte = network.LTE() lte.send_at_cmd('AT+CGDCONT=1,"IP","internetm2m"') lte.attach(band=20) lte.isattached()
And the response is always False.
I update the sequans modem Firmware, but the result is the same.
I came to the conclusion that the sequans fw is not ready for the portuguese network. Or I'm doing something wrong?
danielm last edited by
There is one more issue. Test application was sending MQTT message once per minute. After approx. 5 hours MQTT client returned exception [Errno 113] EHOSTUNREACH and each following attempt to reconnect to MQTT broker was unsuccessful.
The application also checks lte.isattached() and lte.isconnected() in each loop and if there is a change of state it prints out notification. There were no notifications therefore I assume that state of both lte.isattached() and lte.isconnected() remained True.
danielm last edited by
I performed successful tests in NB-IoT network of Slovak Telekom with Sequans FW NB1-38729 and Pycom FW 1.18.1.r2 provided by @Xykon .
As suggested by @peterv it was possible to reduce the code to:
lte = network.LTE() lte.send_at_cmd('AT+CGDCONT=1,"IP","nbiot.telekom.sk"') lte.attach(band=20)
Issues which remain unsolved from my point of view are:
- working DNS over NB-IoT connection
- support of PSM and eDRX
@xykon please advise when we can expect a response to the band 8 problem.
I was surprised to discover that this issue has been known about for 8 months now.
This is a critical stop point for our project. We have already eaten up precious time that we have arranged with Vodafone Australia for system trials.
JoseDLopez last edited by JoseDLopez
@stsiafak Thanks for you answer!
Did you make that test in Chile? If it so, wich operator? I am trying with telefonica/movistar
Finally i am trying with Huawei Node and after:
error +CEREG: 4
It seems to be a problem with freq band selected. Can you guide me about what does that error mean?
Maybe? Error Code: 4 -> Operation not supported
robert-hh last edited by robert-hh
@redferne See thes post of @Xykon below, which try to address this:
Redferne last edited by
Just tried upgrading a FiPy to Stable v1.18.1.r1 and LTE firmware NB1-38729. Seems to attach fine using Telia NB-IoT, however it will not let me connect due to this:
>>> lte.send_at_cmd("at+cops?") '\r\n+COPS: 0,2,"24001",9\r\n\r\nOK\r\n' >>> lte.send_at_cmd("at+cereg?") '\r\n+CEREG: 2,5,"03F4","01A7561C",9\r\n\r\nOK\r\n' >>> lte.isattached() False >>> lte.connect() Traceback (most recent call last): File "<stdin>", line 1, in <module> OSError: modem not attached
Without digging in the code, is <stat> 5 properly handled as registered, roaming?
@kevin So it seems that the decision for Sequans was not a lucky choice.
@xykon Pycom was looking into a "test" firmware from Sequans, supporting all 12 bands:
That was 8 months ago, I guess it didn't work out? Can you look into that option again? Even if not fully calibrated/certified, it would work for lab testing.
@robert-hh The problem is that the underlying modem firmware from Sequans (e.g., NB1-38729) only supports bands 3/4/12/13/20/28. Operations involving other bands silently fail at the modem level, with no effect and no error messages.
Pycom was aware of this from the beginning, but it is still not resolved:
Not sure if it is a lack of support from Sequans, or concerns over certification, or a deliberate strategy to control roll-out with selected partners. In any case it goes against the principle of "open development" that motivated many of us to choose Pycom/Sequans.
@mfalkvidd That is not required. Since lte.attach w/o parameters only send AT commands like:
to the device for the 6 supported bands, an user could also manually send these commands, or would call lte.attach(band=xx). It's only important, that the Sequans firmware could deal with that. And obviously, the should be a link the the docs to a table, where users could find the frequencies of interest.
mfalkvidd last edited by mfalkvidd
@robert-hh with 12 bands to choose from, covering all possible combinations of 6 bands would require pycom to make 665,280 different firmwares available (12 * 11 * 10 * 9 * 8 * 7). I think that would be troublesome.